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peanut reaction, and may be considered for further inhalant testing. All results and
follow up testing must be considered with the history and other clinical findings.

Patients with demonstrated or suspected peach clinical allergy must be considered at
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risk for clinical peanut allergy. In one study , about two-thirds of patients with clinical
sensitivity to both peanut and peach developed clinical reactions to peach before
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peanut. In another earlier study , 32% of patients mono-sensitized to peach LTP
were clinically allergic to peanut. The possible sensitizing effect of lipid transfer protein
(LTP), Pru p 3, and cross-reactivity with peanut LTP, Ara h 9, is suspected to be
involved.

Patients with more than one antibody to a purified allergen have a diverse response
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and are more likely to have strong clinical reactions . Higher specific IgE
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concentrations to purified allergens correlate to more diverse antibody responses .
Also a diverse antibody response in a peanut sensitive patient is correlated with the
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number of organ systems that have clinical reactions to peanut . Therefore the level
of Ara h 2 specific IgE tends to correlate with the severity of response in peanut
allergic individuals.

The total IgE level in each patient can be used with the specific IgE level to Ara h 2 to
calculate the specific activity of Ara h 2:

concentration of Ara h 2 specific IgE = Specific Activity
concentration of total IgE

In house studies have demonstrated that specific IgE to Ara h 2 may represent as
much as 26% of the total serum IgE. One study evaluating the specific IgE/Total IgE
ratio in atopic adults for 182 different allergens found that the average specific activity
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was about 2% . High specific activity to Ara h 2 suggests that mast cells are more
likely to have more Ara h 2 specific IgE molecules bound to their receptors. Natural
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Ara h 2 isoforms are closely associated with effector activity .

The Allermetrix peanut panel uses natural allergens as well as natural purified
allergens that include isoforms in their natural conformation. The liquid allergen
technology ensures that allergens are presented to serum IgE in their natural non-
denatured conformations. The peanut panel has been devised to help the physician
understand how the array of peanut specific IgE antibodies present in a patient’s
serum may indicate different levels of risk for “true” peanut allergy and the potential for
clinical reactions.

When “true” peanut allergy is suspected, tree nuts and sesame seed need to be
evaluated for cross-reactive clinical reactions. Up to 50% of peanut allergic patients
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have or develop allergy to tree nuts . Ara h 2 has been shown to cross-react with
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both almond and brazil nut . In peanut allergic individuals who also have tree nut
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allergy, the likelihood of sesame seed allergy is greatly increased .

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